Process of manufacturing tipless incandescent lamps



Dec. 27, 1927.

G. F. WEBB PROCESS 0F IANUFACTURING lTIILSVS INCANDESCENT LAMPS Filed April, 14, 1927 .gzfft/ Patented Dec. 27, 1927.

PATENT OFFICE.

GEORGE F. WEBB, OIF HAMILTON, ONTARIO, CANADA.

PROCESS OF MANUFACTURING TIIPLESS INCANDESCENT LAMPS.

Application led April 14, 1927, Serial No. 183,795, and in Canada April 23, 1926.

rlhis invention relates to improvements in the process of manufacturing the stem bodies of tipless incandescent lamps, and more particularly to an improved method of uniting the exhaust tube ot' glass to the homogeneous leading-in tube.

The invention fur-ther relates to an improvement in the process disclosed in my Pat-ent No.1,580,226 of April 13th, 1926. The process described in this patent relates to a method of uniting the exhaust tube with the leading-in tube during the step ot' uniting the filament stem with the latter mentioned tube, and consists of axially aligning the filament stem and exhaust tube with their adjacent ends within the leading-in tube, fusing to ,plasticity and producing masses coalescence oi' the end of the filament stem and the proximal portion ot' Vthe leading-in tube, thereby causing the end of the exhaust tube to bend toward the walling ot' the leading-in tube by thermoattraction and become Welded to said Walling adjacent the mass, then introducing a current into the exi haust tube from its outer end and blowing an opening in the junction part ot the two tubes Due sometimes to imperfection in the exhaust tube, or an inequality or inadequacy of material, or imperfect adjustment in setting up the parts, the exhaust tube would fail to properly weld to-the leading-in tube, with the resultant waste oi' all the parts.

rlhe important object ot' the present invention, therefore, is to provide means for assuring the proper o erative union of the eXf haust tube and lea ing-in tube, and the invention consists essentially of utilizing an exhaust tube provided with an enlarged hollowv globular body on that end of the same which is to be Welded to the leading-in tube, or, producing such an enlarged portion during the process of making the lamp.

Now it appears that the production of the enlarged globular portion or body on the end of the exhaust tube necessitates an additional step in the process of manufacturing the lamps, and prolongs and involves the process, but, the material conserved thereby fully Warrants the more intricate'procedure.

Aattained in the manner which will be. hercinat'ter more particularly described, illustrated in the accompanying drawing, and ascertained in the claims hereunto annexed.

Referring to the drawing:

Figure 1 is an elevation 'of an exhaust tube prior .to its being treated and connected or 'united to the leading-in Atube;

Figure 2 is an elevation of the exhaust tube as being in course of subjection to a plastic homogenous foreign body in accordance with this invention;

Figure 3 is an elevation of the exhaust tube as having acquired a portion of the foreign body of glass in the form of a glass node;

Figure 4 is an elevation of the exhaust tube showing the formation of the enlarged hollow globular body thereon;

Figure 5 is a sectional elevation of the exhaust tube, leading-in tube, lilament stem, u

the lead wires, in position as in preparation :tor coalescence by apphcation of heat;

F1gure (3 is a sectional elevation of the 'stem body comprised ot the units charac tei-ized in the description ot Figure 5 subsequent to the consummation of coalescence; and, y

Figure 7 is an elevation of the structure shown in Figure 6 as seen as having been given a quarter revolution on its axis.

Similar reference characters relier to corresponding parts throughout the several views.

The exhaust tube is designated on the drawing by the numeral 12, the leading-in tube by 13, the lilament stem by 14, and the lead Wires by 15. These latter' have no part in the present invention and are shown merely because they :torm part of the stem body, and are embodied therein in the Well known usual manner.

The important feature of the invention is the enlarged hollow globular body on the inner end of the exhaust tube 12 before said tube is united tothe leading-in tube 13. This exhaust tube comprises a length of tubular glass as shown in Figure 1, and the i end of which is later to be Welded to the to a glass mass 1G which is in a like leading-iu tube 13, is subjected to an application of heat which reduces this part of the glass tube to plasticity and seals the end of the tube, and while it is thus plastic it is, by direct contact, applied momentarily plastic state. The object of this application is to annex to the end of the exhaust tube by capillary attraction and molecular adhesion some of the glass from the mass 1G and thus produce temporarily a node 17 of massed glass upon said end, as in Figure 3. In this manner the end of the tube is supplemented in material.

Immediately subsequent to the production of the node 17. and before it chills, a gentle current of air or the like is applied to the opposite or open end of the tube, as from the nozzle 18 for example. rlhis current enters the core of the tube, expanding the node 17 to form the enlarged hollow globular body 19, as in Figure 4. The exhaust tube'is now prepared for welding to the leading-1n tube 13.

In completing the process of forming the stem body, the exhaust tube l2 is inserted within the leading-in tube 13 from the iiared end of the` la'tter mentioned tube, and the filament stem 14 is inserted from the opposite end of the leading-in tube in axial alignment with the exhaust tube, but spaced from the globular body 19, as in Figure and the lead Wires are also positioned. Heat is now applied to the end of the leading-in tube 13 and the proximal end of the filament stem; and when fused these parts coalesce and are subsequently. pressed together in a flat mass 20 by a suitable clamping device. During this fusion and coalescence of the leading-in tube and filament stem, the proximal portion of the walling of the leading-in tube and the enlarged globular body 19, which are very close together, as will be noted, become semi-molten or plastic, and the latter by thermo-attraction yields to the walling of the leading-in tube and adheres thereto. As the said body 19 is thus welded to the walling of the leading-in tube, before the parts chill, a comparatively strong current of air or the like is introduced to the outer open end of the exhaust tube, and the current thus introduced blows out the film ofl plastic glass which theretofore closed the Welded end of said tube and the registering portion of the walling of the leading-in tube. This establishes the objective communica,- tion from the exterior of the leading-in tube to the interior of the exhaust tube at 21, as in Figures 6 and 7. These figures show the completed stem body.

I claim:

1. The method of assembling the stem body of incandescent lamps comprising leading-in tube, exhaust tube, ilament'stem, and

lead Wires, which consists of forming an enlargcd hollow globular bo'dy on one end of the exhaust tube, inserting within the leading-in tube that end part of the exhaust tube having said. globular body, inserting one end part of the filament stem within the leadingin tube from the opposite end thereof, placing the lead wires, fusing to plasticity and producin, r massed coalescence of the end part of thc .filament stem and the proximal portion of the leading-in tube, thereby also inducing said globular body, by thermo-attraction, to yield to the nearest portion of the walling of the leading-in tube and by molecular adhesion to weld itself thereto adjacent the mass formed aforesaid, and then introducing a current into the exhaust tube from its outer end while the material at the junction of said tubes is yet plastic, thereby blowing an opening at said junction to estab lish an objective communication from out side the leading-in tube to inside the exhaust tube.

2. The method of assembling the stem body of incandescent lamps, which consists of inserting Within a leading-in tube an exhaust tube having an enlarged hollow globular body on the end entering the leading-in tube, inserting one end part of a filament stem within the leading-in tube from the opposite end thereof, placing lead wires, fusing to plasticity and producing massed coalescence of the end part of the filament stem and the proximal portion of the leadingin tube, thereby also inducing said globular body, by thermo-attraction, to yield to the nearest portion of the Walling of the leadingin tube and by molecular adhesion to weld itself thereto adjacent the mass formed aforesaid, and then introducing a current into the exhaust tube from its Outer end while the material at the junction of said tubes is yet plastic, thereby blowing an opening at said junction to establish an objective communication from outside the leading-in tube to inside the exhaust tube.

3. The method of assembling the stem body of incandescent lamps comprising lead ing-in tube, exhaust tube, filament stem, and lead wires, which consists offusing to plas` ticity and lscaling one end of the exhuast tube, supplementing the sealed end of the exhaust tube by the annexation of homogenous material thereby forming anode thereon, expanding the node by introducing a cur rent into the exhaust tube and thereby forming an enlarged hollow globular bo'dy, inserting within the leading-in tube that end part of the exhaust tube having said globular body, inserting one end part of the filament stem Within the leading-in tube from the opposite end't-hercohplacing the lead Wires, fusing to plasticity and producing massed coalescence of the end part of the filament stem and the proximal portion of the leading-in tube, thereby also inducing said globular body, by thermo-attraction, to yield tubes is -yet plastic, thereby blowing an open to the nearest portion of the `Walling of the ing at said junction to establishI an objective leading-in tube and by molecular adhesion to communication from outside the leading-in l04 weld itself thereto adjacent the mass formed tube to' inside the exhaust tube. 5 aforesaid, and then introducing a current In testimony whereof he has affixed his siginto the exhaust tube from its outer end nature.

while the'material at the junction of rsaid GEORGE F. WEBB. 

